George edwin shaw



- (No Model.)

G. E. SHAW.

TELEPHONE RECEIVER.

Patented May 1 UNITED STATES PATENT OFrIcn GEORGE EDWIN SHAW, OFCHICAGO, ILLINOIS, ASSIGNOR TO THE SHAW TELEPHONIG COMPANY OF AMERICA.

TELEPHONE-RECEIVER.

SPECIFICATION forming part of Letters Patent No. 276,723, dated May 1,1883.

Application filed October 2,1882. (No model.)

I all whom it may concern:

Be itknown that I, GEORGE EDWIN SHAW, a citizen of the United States ofAmerica, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inTelephone-Receivers,

, of which the following is a specification.

In the drawings, Figure 1 is a side view of a receiver embodying myinvention. Fig. 2 is a vertical section thereof. Fig. 3 is a top or planview of the same, showing the cap or core removed; and Fig. Iis anisometrical perspective view of the magnet detached.

Like letters of reference indicate like parts.

A is the head, ease, or shell, which has thereon a knob, to, tofacilitate handling.

B is the cap, which has a central opening,

6, and the exposed or outer face of which is made flaring or convergingtoward the said opening.

O and U are binding-posts. I make no special claim to the parts A a B band (J C, as

' my invention relates to the magnet and its accessories. These novelfeatures I will now proceed to describe.

D represents my improved magnet. This magnet is circular in form, thoughnot a complete annulus, as :it is severed or slit vertically, as shownat c.

E is a horn or extension attached to or forming a prolongation of onepole only, and pro jecting radially inward to or nearly to the center ofthe magnet, and thence extending vertically upward to receive the spool.

F is the. spool, which is mounted on the ver-' deal orupwardly-projecting arm of the horn E, which serves as a spindleor corefor the spool. 3

G is the wire or inducing-coil. One end of the coil or wire G passes tothe binding-post O, and the other end is wound to and from on theoutside or periphery of the magnet, passing over pins cl d, as shown. Itis then carried through the magnet to the other bindingpost, 0.

In order that the part of the wire which is wound around the outside orperiphery of the magnet may not be injured by contact with the case, Ideem it best to flange the magnet, as shown at e e, to prevent the wirefrom slip: ping off over the edge of the magnet.

H is an indie-rubber gasket or mat, placed between the base of themagnet and the case A, which serves by its elasticity to secure a closercontact between the upper surface or edge of the magnet and theperiphery of the disk I when the cap or cover B is fitted on the case A,and also plays an important part in giving to the magnet a massvibratiornwhich I believe, in combination with the molecular vibrationresulting from changes in magnetic tension, modifies and renders audiblefine details of articulation unknown in instruments of ordinaryconstruction.

In the example shown, the magnet I), its

horn E, and the spindle or core are made in 7 one piece, whether cast orforged. I deem that mode of construction preferable; but the born orcore can be made in separate. pieces from the magnet and afterwardsecured thereto in any suitable manner. The magnetization of theincomplete annulus may be effected by temporary contact of its ends(which are opposite to each other at the slit, as described) with therespective poles of a powerful electroma-gnet. It is not absolutelyessential that the wire G should be wound to and from on the outside ofthe magnet D; but I prefer to so wind that part of the magnet, as itsmagnetic inducing action is thereby modified.

I is the disk or diaphragm ofmagnetic metal. The disk I rests on theupper or outer edge of the magnet D, thus becoming an armature.

I am aware that a diaphragm supported at its periphery bymagnetic polesof unlike name to that opposed to the center of said diaphragm is notnew; but in my form of telephone the diaphragm is supported by twoopposite poles, which induces in said diaphragm a complex magneticcondition not easily ex plained, but which, in conjunction with thesingle polarity of the central arm of the magnet, produces more clearand perfect articulation. The iron diaphragm acts in some degree as anarmature or keeper with reference to two points, at least, of themagnet-to wit, the two ends of the incomplete annulus. The two poles ofthe incompleteannulus proper, being bridged by and in contact with thediaphragmarmature, induce therein, as before stated, a

complex magnetic condition. In this condition it then becomes withoutcontact an armature to the central core, becoming still more complex inits condition as it vibrates toward or away from the same, and the massmovement or vibration of the magnet allowed by its elastic support andimparted thereto by but not synchronous with .that of the diaphragmgives clear and due definition to obscure tones, as before set forth.The winding of insulated wire around the incomplete annulus in the lineof its polarity, hereinbefore alluded to, adds another useful element tothe combination, and adds materially, as demonstrated by experiment, tothe effectiveness of the instrument.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-.-.

1. In atelephone receiver, an incomplete annulus permanently magnetic,the magnetic poles opposite each other at the break in said annulus, andhaving a neutral point nearly diametrically opposite said break, saidannulus supporting by its periphery a magnetic circular diaphragm,'andhaving in its center a vertically-projecting arm conneotedwith one poleonly of said annulus, and encircled by coils of insulated wire,substantially as described.

2. In a telephone-receiver, the combination of a permanentmagnet havingthe form of an incomplete annulus having its poles at"t h'e break,with acore projecting centrally and vertically from one end of the incompleteannulus, carrying a coil of insulated wire wound to and from on theouter face of the annulus, which is electrically connected with saidcoil, a diaphragm of magnetic material in contact with the annulus, butnot with the core, and an elastic support for the magnet, allsubstantially as described.

In witness whereof I affix my signature in presence of two witnesses.

, GEORGE EDWIN SHAW.

Witnesses: Y

CHAS. S. BATES, I A. S. TAYLOR.

